UBC Faculty of Medicine researchers have found that reducing twin and triplet pregnancies to singleton or twin pregnancies was associated with a substantial reduction in complications, such as pre-term birth and very pre-term birth.

Although rates of death and serious illness were not lower among all multi-fetal pregnancies that were reduced, pregnancies that resulted from fertility treatments did show a significant reduction in rates of death or serious illness following fetal reduction.

Multiple births of twins and triplets — and the associated health risks — have increased in many high-income countries, with a respective twofold and threefold increase in recent decades. In Canada, triplet births or higher have increased from 52.2 per 100 000 live births to 83.5 between 1991 and 2009, mainly because of an increase in fertility treatments for older women of child-bearing age.

The UBC research, published in CMAJ (Canadian Medical Association Journal), looked at birth outcomes in British Columbia between 2009 and 2013 among women who underwent elective fetal reduction of multi-fetal pregnancy compared with multi-fetal pregnancies without such reduction. Among the 208,827 women who gave birth during the study period, 95 (0.04%) underwent fetal reduction, with 45 women delivering twins and 50 delivering singletons.

Neda Razaz

“The fetal reduction-associated decrease in pre-term birth and low birth weight overall, combined with the decrease in death and serious illness among babies of women who conceived following fertility treatments, suggests that fetal reduction in multi-fetal pregnancy offers substantial benefits,” said lead author Neda Razaz, who did the research as a UBC doctoral student with senior author K.S. Joseph, a Professor in the Department of Obstetrics and Gynecology and the School of Population and Public Health.

Women who underwent fetal reduction were more likely to be older and of a higher socioeconomic status and significantly more likely (75 per cent compared with 3.3 per cent) to have undergone fertility treatment.

The authors note that they had limited details on the timing, reason and number of fetuses reduced in some pregnancies. They note that physicians need to be sensitive when discussing the risks and benefits of fetal reduction with parents.

“Clinicians counselling women with multi-fetal pregnancy should be aware of the potential for substantial parental stress resulting from fetal reduction procedures, including negative feelings such as guilt, regret and grief,” the authors conclude.